In order to realize reactive power compensation of low voltage distribution network with low cost, large capacity and dynamic continuity, a hybrid reactive compensation system based on thyristor switched capacitor (TSC) and static var generator (SVG) is proposed. The advantages of TSC low cost and large capacity reactive power compensation and SVG dynamic continuous reactive power compensation are combined in this system. Based on the analysis of its basic principles, a hierarchical coordination control strategy is proposed to eliminate the influence of TSC and SVG on its hybrid reactive compensation performance because of the differences in response speed. Aiming at the safe operation of hybrid reactive compensation system under unbalance grid voltage, the control strategy of double-loop superposition of positive and negative sequence of SVG is studied. So that a certain degree of unbalance voltage can be suppressed, at the same time with dynamic reactive power compensation performance, to ensure the safe and stable operation of the system. Finally, the correctness of the proposed control strategy is verified through simulation.
